A nanowire is a wire structure having a nanometer unit size wherein it has various diameter sizes of from less than 10 nm to several hundreds nm. In this nanowire, there are advantages such as an electron movement property depending on a specific direction or an optical property of a polarization phenomenon. As a result, the nanowire has been used in various fields of photo diode such as a laser, transistor and memory element, or the like as a next generation technology.
Currently, even though a study of a manufacturing method and material property for nano particles has been actively made, a study of a manufacturing method of nanowire has been minutely made. An existing representative nanowire manufacturing method is shown in FIG. 1 as a Vapor-Liquid-Solid (VLS) growth method.
The VLS growth method is used for manufacturing a nanowire as following steps. Firstly, a substrate 11 is prepared, as shown in FIG. 1(a), and then a metal layer 12 is formed on the substrate 11 by applying metal such as Au, as shown in FIG. 1(b). After that, the substrate provided with the metal layer is heat-treated at about 500° C. and then the substance on the metal layer 12 is agglomerated and as a result a metal catalyst 13 is formed, as shown in FIG. 1(C). At this time, the metal catalyst 13 each usually has irregular size, instead of regular size. After that, a nanowire 14 is formed based on the metal catalyst as a nucleation place, as shown in FIG. 1(d). Here, the nanowire 14 may be formed by supplying SiH4, or the like of silicon hydrogen compound to the metal catalyst 13 and inducing the Si element of SiH4 at a process temperature and at the metal catalyst place to form nucleus. When silane is supplied continuously thereto, the nanowire can growth continuously under the metal catalyst 13, as shown in FIG. 1(d). According to the VLS growth method, the nanowire may be formed in a desired length by adjusting properly the amount of material gas such as silane; however, there is a limitation to a maximum length when forming the nanowire, and further mass production is not proper since high temperature heat treatment is essential. Further, the nanowire growths under limitation to a diameter of the metal catalyst 13 and a distribution thereof wherein a precise width (thickness) and the distribution is difficult to be adjusted and impurity contamination may be made within the nanowire by the metal catalyst.
Additionally, the VLS growth method is high cost in process and is not proper for mass production, and thus the VLS growth method is not proper for mass production of the nanowire.